When building roadways, parking lots and the like, for example, paving machines may be used to deposit paving material, such as asphalt, on a paving surface to create a flat, consistent surface over which vehicles will travel. A paving machine at the construction site, such as an asphalt paver, is generally a state-of-the art self-propelled construction machine designed to receive, convey, distribute, profile and partially compact the asphalt material. The paving machine accepts asphalt material that is heated to an appropriate temperature for flow and even spreading into a receiving hopper at the front of the machine. The asphalt material in the hopper is conveyed to the rear of the machine with parallel slat conveyors or other types of conveyors positioned at the bottom of the hopper. The asphalt material conveyed from the hopper is distributed along the width of an intended ribbon or mat by means of two opposing screws or spreading conveyors or augers, and a free-floating screed profiles and compacts the asphalt material into a mat on the paving surface.
The operation of the paving machine and its components may be manually controlled by the operator(s) to dispense the asphalt material and create the mat on the paving surface. In many paving machines, systems are provided to automate and control the paving process for consistent operation of the paving machine for laying a uniform mat on the paving surface without defects compromising the integrity and longevity of the mat. The automation systems may include control over the speed of the paving machine, operation of the conveyors and augers to distribute the asphalt material, and vertical positioning and temperature control of the screed. The control settings may be established during an initial setup process for a paving job, such as the paving of a stretch of a highway or the paving of a parking lot.
When operating the paving machine in the automated mode under the guidance of the control system, it may become necessary at times during the paving job for an operator to manually intervene in the automated operation of the paving machine to address conditions arising as the asphalt mat is being laid. Such manual interventions may or may not affect the quality of the asphalt mat. For example, when the hopper is nearly emptied of a load of asphalt material, the paving machine may need to be stopped to wait for a truck to arrive with a fresh load of asphalt material to refill the hopper. During the time that the paving machine is stopped, asphalt material in a pile behind the machine and in front of the screed, or in the newly-formed mat positioned under the screed, may settle or cool so that a lump where the pile sits or depression in the mat under the screed may be left when the paving machine begins moving after the hopper is refilled.
Before refilling the hopper, material collecting at the sides of the hopper may be fed to the conveyors by manually activating actuators for raising the right and/or left side of the hopper. A temperature gradient may exist so that the asphalt material at the sides of the hopper is cooler than the asphalt material at the middle of the hopper. The cooling may cause a loss of moisture and compaction of the asphalt material that can affect the quality of the mat formed from the cooled material. In other situations, control of the conveyors may cause too little asphalt material to flow from an otherwise full hopper and create a risk of starving the screed by providing too little material to fully form the mat. When this occurs, the operator may manually override the conveyor speed to increase the flow of asphalt material from the hopper. The conveyor speed increase may cause a sudden surge of asphalt material that can cause a bump, cold spot or material segregation in the mat.
Systems exist for detecting construction equipment process failures. One such system is disclosed in U.S. Pat. No. 7,898,403, entitled “Detecting Construction Equipment Process Failure” and issued to Ritter et al. on Mar. 1, 2011. According to one embodiment of the reference, information about a construction equipment asset from a reporting source is received. A database is the populated with the information. A process failure report is provided if the construction equipment asset is operated in a manner which violates a process norm assigned to the construction equipment asset. This reporting applies to failures of the construction equipment, but not to manual interventions by operators that are not equipment process failures as discussed herein and that do not necessarily relate to equipment failures.
In currently known paving machines, these types of manual interventions occur and may or may not be noted by the operators in a job log or other formal or informal reporting format. Where they are not logged by the operators, repetitive, systematic errors in laying the asphalt mat may be occurring without knowledge of the paving contractor and customer. Problems may be occurring that are not immediately apparent, but may lead to premature degradation and replacement of the current and other surface that may be preventable if the issues were timely diagnosed. In view of this, a need exists for improved identification and evaluation of manual actions taken by paving machine operators that indicate conditions or situations that compromise the integrity of the asphalt mat.